Human activities have caused approximately 1 degree Celsius of global warming since pre-industrial times. The report analyzes pathways to limit warming to 1.5 degrees Celsius by 2100 in order to reduce risks and impacts of climate change. It finds that global CO2 emissions must decline substantially before 2030 and achieve net zero emissions by 2050. This will require rapid transitions across all sectors including energy, transportation, buildings, agriculture and land use. Limiting warming to 1.5 degrees can significantly reduce climate risks and impacts compared to 2 degrees, but requires unprecedented global cooperation and action.

1. Global Warming of 1.5°C
Valérie Masson-Delmotte
Co-chair, IPCC Working Group I (Physical Science Basis)
valmasdel

2. The report in numbers
91 Authors from 40 Countries
133 Contributing authors
6000 Studies 1 113 Reviewers
42 001 Comments

3. Where are we?
Since pre-industrial times, human activities have
caused approximately 1.0°C of global warming.
• Already seeing consequences for people,
nature and livelihoods
• At current rate, would reach 1.5°C between
around 2030 and 2050
• Past emissions alone do not commit the
world to 1.5°C
Ashley Cooper / Aurora Photos

4. Cumulative emissions of CO2 and future non-CO2 radiative forcing
determine the probability of limiting warming to 1.5°C|

5. Cumulative emissions of CO2 and future non-CO2 radiative forcing
determine the probability of limiting warming to 1.5°C|

6. Cumulative emissions of CO2 and future non-CO2 radiative forcing
determine the probability of limiting warming to 1.5°C|

7. Cumulative emissions of CO2 and future non-CO2 radiative forcing
determine the probability of limiting warming to 1.5°C|

8. Cumulative emissions of CO2 and future non-CO2 radiative forcing
determine the probability of limiting warming to 1.5°C|

9. Cumulative emissions of CO2 and future non-CO2 radiative forcing
determine the probability of limiting warming to 1.5°C|

10. Faster immediate CO2
emission reductions limit
cumulative CO2 emissions
Cumulative emissions of CO2 and future non-CO2 radiative forcing
determine the probability of limiting warming to 1.5°C|

11. Maximum temperature rise is determined by
cumulative net CO2 emissions and net non-CO2
radiative forcing due to methane, nitrous oxide,
aerosols and other anthropogenic forcing agents.
Cumulative emissions of CO2 and future non-CO2 radiative forcing
determine the probability of limiting warming to 1.5°C|

12. Spatial patterns of changes in annual mean temperature and precipitation
26 CMIP5 models; hatching : 66% model agreement
Global warming of 1.5°C 2°C

13. Spatial patterns of changes in extreme temperature and precipitation
Number of hot days
(days)
Temperature of
hottest days (°C)
Temperature of
coldest nights (°C)
Extreme
precipitation (%)
Global warming of 1.5°C 2°C

14. Arctic summer sea-ice
 L maintained; 50% or higher risk to be ice free; VL to be ice free
 Habitat (polar bear, whales, seals, sea birds) : losses; losses; critical losses
 Arctic fisheries : benefits; benefits; benefits
Warming of 1.5°C or
less
Warming of 1.5ºC-2°C
Warming > 2°C
L, likely
VL, very likely
LC, low confidence
MC, medium confidence
HC, high confidence
Emergence and intensity of regional climate change hot spots

15. Warming of 1.5°C or less
Warming of 1.5ºC-2°C
Warming > 2°C
L, likely
VL, very likely
LC, low confidence
MC, medium confidence
HC, high confidence
Arctic land regions
 Cold extreme: warm up to 4.5°C (HC); warm up to 8°C (HC); VL drastic warming
 Tundra : L biome shifts; L more shifts; drastic biome shift possible (LC)
 Permafrost : L 17-44% reduction; L larger (28-53%); potential for collapse (LC)
 Boreal forest : increased mortality at S. boundary (MC); further (MC); potential dieback (LC)
Emergence and intensity of regional climate change hot spots

16. Warming of 1.5°C or less
Warming of 1.5ºC-2°C
Warming > 2°C
L, likely
VL, very likely
LC, low confidence
MC, medium confidence
HC, high confidence
Alpine regions
 Biomes : L severe shift; L even more severe; L critical
Emergence and intensity of regional climate change hot spots

17. Warming of 1.5°C or less
Warming of 1.5ºC-2°C
Warming > 2°C
L, likely
VL, very likely
LC, low confidence
MC, medium confidence
HC, high confidence
Mediterranean
 Extreme drought: increase probability(MC); robust increase(MC); robust and large increase(MC)
 Runoff decrease: about 9% (MC); about 17% (MC); substantial reductions (MC)
 Water deficit: risk (MC); higher risks (MC); very high risks (MC)
Emergence and intensity of regional climate change hot spots

18. Warming of 1.5°C or less
Warming of 1.5ºC-2°C
Warming > 2°C
L, likely
VL, very likely
LC, low confidence
MC, medium confidence
HC, high confidence
Tropics
 # hot days and nights, heatwaves: increases (HC); largest increase; oppressive, VL health impact
 Livestock heat stress : increased; onset of persistent (MC); L persistent
 Crop yields: risks; extensive risks (W. Africa, SE Asia, S. America); VL substantial reductions
 Rainforests : reduced biomass; larger reductions; reduced extent, potential forest dieback (MC)
Emergence and intensity of regional climate change hot spots

19. Warming of 1.5°C or less
Warming of 1.5ºC-2°C
Warming > 2°C
L, likely
VL, very likely
LC, low confidence
MC, medium confidence
HC, high confidence
Southeast Asia
  flooding related to sea-level rise: risks; higher risks (MC); substantial increases in risk
 Asian monsoon : LC; LC; L increase in precipitation intensity
 Heavy precipitation: increase; stronger increase (MC); substantial increase
 Crop yield reductions: -; one third decline in per capita (MC); substantial reduction
Emergence and intensity of regional climate change hot spots

20. Warming of 1.5°C or less
Warming of 1.5ºC-2°C
Warming > 2°C
L, likely
VL, very likely
LC, low confidence
MC, medium confidence
HC, high confidence
West African and the Sahel
 Monsoon : uncertain ; uncertain ; strengthening (LC)
 Hot nights, longer, more frequent heat waves: L ; L further ; VL substantial 
  in maize and sorghum production: L, about 40%  suitable area; L larger ;
major regional food insecurities (MC)
 Undernutrition risks : increased; higher; high
Emergence and intensity of regional climate change hot spots

21. Warming of 1.5°C or less
Warming of 1.5ºC-2°C
Warming > 2°C
L, likely
VL, very likely
LC, low confidence
MC, medium confidence
HC, high confidence
Southern Africa
 Water availability: reductions (MC); larger reductions (MC); large reductions (MC)
 # of hot nights and  heat waves : increases (HC); further increase (HC); drastic increase (HC)
 Increased mortality from heat-waves: high risks; higher risks (HC);
sustantial impact on health and mortality (HC)
 Undernutrition / dryland agriculture and livestock: high risk; higher risk (HC); very high risks
Emergence and intensity of regional climate change hot spots

22. Small islands:
 Inundation risk : land exposed; tens of thousands displaced ; substantial, widespread impacts
 Coastal flooding: risks; high risks ; substantial and widespread impacts
 Fresh water stress : increased; projected aridity; substantial and widespread impacts
 # of warm days : increase; further increase (70 warm days/year), persistent heat stress in
cattle ; persistent heat stress
 Loss of coral reefs: 70-90%; most coral reefs ; loss of most coral reefs (VL)
Warming of 1.5°C or less
Warming of 1.5ºC-2°C
Warming > 2°C
L, likely
VL, very likely
LC, low confidence
MC, medium confidence
HC, high confidence
Emergence and intensity of regional climate change hot spots

23. Confidence level : M, medium; H, high; VH; very high
How do climate-related risks change
as a function of the level of global warming?| Very high
High
Moderate
Undetectable

24. Confidence level : M, medium; H, high; VH; very high
How do climate-related risks for “Reasons For Concern” change
as a function of the level of global warming?|
Very high
High
Moderate
Undetectable

25. At 1.5°C compared to 2°C
• Up to several hundred million fewer people
exposed to climate-related risk and
susceptible to poverty by 2050
• Disproportionately high risk for Arctic,
dryland regions, small island developing
states and least developed countries
• Lower risks for health, livelihoods, food
security, water supply, human security and
economic growth
Jason Florio / Aurora Photos
• Wide range of adaptation options which can
reduce climate risks; less adaptation needs at
1.5°C

26. 26
What are greenhouse gas emission pathways
compatible with limiting warming to 1.5°C?
https://data.ene.iiasa.ac.at/iamc-1.5c-explorer/
|

27. 27
What are greenhouse gas emission pathways
compatible with limiting warming to 1.5°C?
|
Pathways with no or limited overshoot
Pathways with a high overshoot

28. 28
What are greenhouse gas emission pathways
compatible with limiting warming to 1.5°C?
|

29. Limiting warming to 1.5°C
Would require rapid, far-reaching and
unprecedented changes in all systems
A range of technologies and behavioural changes
Scale up in annual investment in low carbon energy
and energy efficiency by factor of five by 2050
Mint Images / Aurora Photos
Renewables supply 70-85% of electricity in 2050
Coal declines steeply, ~zero in electricity by 2050
Deep emissions cuts in transport and buildings
Transitions in land use, scale depending on
mitigation portfolio
Urban and infrastructure system transitions,
changes in urban planning practices

30. Where are we?
• National pledges are not enough to limit
warming to 1.5°C
• Avoiding warming of more than 1.5°C
would require carbon dioxide emissions to
decline substantially before 2030
Peter Essick / Aurora Photos

31. • Different pathways have different synergies
and trade-offs with UN Sustainable
Development Goals (SDGs)
• Careful mix of measures to adapt to climate
change and reduce emissions can help
achieve SDGs
Ashley Cooper/ Aurora Photos
• Ethical and fair transitions
• Low energy demand, low material
consumption and low carbon food carry
highest benefits• Cooperation, governance, innovation and
mobilisation of finance key for feasibility
Climate change and sustainability

32. Every half a degree matters
Every year matters
Every choice matters

33. ipcc.ch/report/sr15 :
Summary for Policy Makers
10 Frequently Asked Questions
5 Chapters
Glossary

34. The Physical
Science Basis
The Synthesis
Report
Climate Change
Impacts,
Adaptation and
Vulnerability
Mitigation
of
Climate Change
April 2021 April 2022October 2021
July 2021
Global stocktake
2023
UNFCCC
Global
warming of
1.5 o
C
Oct. 2018 Sept. 2019
Aug. 2019
Talanoa
dialogue
UNFCCC
Land
Oceans
and cryosphere
Emission
inventories
May 2019
The IPCC Sixth Assessment Cycle

35. Thank you for your attention

36. Year
BilliontonsCO2peryear(GtCO2/yr)
Agriculture, forestry, land use
Bioenergy with CCS
Fossil fuels and industry
Four illustrative model pathways|